God is visible through clean heart- says Jesus, what really as it means-

That means that only a person who has excellent ethics/morality and who has apologized to those s/he has injured is able to **understand God**. This is because only that kind of person doesn't have an egoistic hidden or overt agenda that causes that person to have a warped view.

In order to fellowship with God you must have a clean heart, that is you have repented of sin and seek God out of pure motives

I think it means to live a Christ like life. To represent Christ in Word and in deed